|Chen, Xian - IOWA STATE UNIVERSITY|
|Imsande, John - IOWA STATE UNIVERSITY|
Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 10, 1998
Publication Date: N/A
Interpretive Summary: Genetic recombination is one of the major sources in generating genetic diversity in plant evolution process as well as in crop breeding programs. This paper reports eight new mutants generated by recombination at a specific soybean chromosomal region. Even more pieces of genetic information were missing at this chromosomal region in some of the crosses. .This discovery of the new mutants will be beneficial to soybean breeders and soybean researchers regarding how to generate plants with genetic diversity using these mutants.
Technical Abstract: Eight new mutants were isolated at the k2 Mdh1-n y2O chromosomal region in soybean [Glycine max (L.) Merr.]. Among them, Genetic Type T234 is yellow foliage and malate dehydrogenase 1 (Mdh1) null, cultivar 'Mandell' is green foliage and Mdh1 null. T234 and Mandell were isolated by screening soybean germplasm for malate dehydrogenase variants. CD-9 is a yellow foliage and Mdh1 null mutant identified in a gene-tagging study with the w4-m mutable line. X-193, X-194, PR-95-649, and PR-95-650 are yellow foliage mutants with Mdh1 null and tan saddle seed coat phenotypes identified in the F2 generation from the cross of T239 (k2) with PI 567.630A (Mdh1-n) designed to determine recombination between the k2 and Mdh1-n loci. A95-K55 is a yellow foliage and Mdhl null mutant with tan saddle seed coat phenotype identified in the F2 generation from the cross of T239 (k2) with T319 (cyt- Y7). Allelism and inheritance studies were conducted with these eight mutants. The results indicated that the yellow foliage mutants were conditioned by a single recessive nuclear locus and were allelic at the y2O locus. In addition all eight Mdh1 null mutants were allelic at the mdh1-n locus. The occurrence of the X-193, X-194, PR-95-649, PR95-650, and A95- K55 mutants were hypothesized to be due to mutations at the Mdh1 Y20 loci in T239, which resulted in k2 Mdh1-n y2O gametes being produced. Finally, gene symbols were proposed for these eight new mutants and the original gene symbol y15 for T234 has been deleted.